Animal bite - in US racoon or bat, in other countries - dogs (dogs are vaccinated in US)

Prognosis for rabies infection

Very poor - almost always fatal if not vaccinated after exposure

Describe symptoms of rabies

First incubation period - asymptomatic
In 2-10 days get fever, headache, anorexia, fatigue and GI symptoms
Neurological symptoms - HYDROPHOBIA - very afraid of water (even glass of water), hallucinations, disorientation, paralysis, confusion, delerium
Then coma, cardiac arrest and death

How do you diagnose rabies

- History of bite
- Negri bodies - cytoplasmic inclusios when study animal or at autopsy

Name filoviridae virus

EBOLA

Shape, strand, symmetry and naked/enveloped for filoviridae virus

Filamentous negative stranded RNA virus
Enveloped
Helical

Ebola virus causes what

Severe (usually fatal) hemorrhagic fever
- Endemic to Africa

Name Bunya virus

Hantavirus (Sin Nombre)
- Endemic to South West

Hantavirus is spread how

Through mice - inspiration of feces

Hantavirus causes what

Hemorrhagic destruction of the lungs and lethal pulmonary complications
- Starts with fever, flu like syndrome and painful muscle aches

Name rio virus

Rota virus - infant diarrhea
- Segmented RNA

Name main orhomyxovirus

INFLUENZA - A, B, C

Type A influenza infects _
Type B influenza infects _

Type A - animals + people
Type B - people only

Describe structure of influenza virus

- Negative stranded RNA
- Enveloped
- Segmented (8 segments)

Envelope of influenza has 2 components - what are they

- HA - hemoagglutinin
- NA - neuroaminidase

If we say Flu is H5N1 - what does that mean

H - hemoagglutinin
N - neuroaminidase

Why can Influenza (RNA virus ) have many strains while DNA viruses can only have one strain

DNA viruses have DNA polymerase which proofreads nucleic acid sequences and so prevents mutations
RNA polymerase can not proofread - and so frequent mutations occur which result in multiple strains

Antigenic shift in Influenza

Sudden and major change in the virus results in appearance of completely new virus and general population does not have Ab's against this new virus so it spreads fast and infects and kills many people
- Causes pandemics (Avian flu)

Describe mechanism of antigenic shift in influenza

- Animal gets infected with two different A viruses at the same time
- RNA in influenza is segmented so two viruses swap segments creating a completely new virus which immune system cannot recognize

Which viruses can undergo antigenic shift

ONLY type A influenza viruses - only those viruses can infect both animals and people

Antigenic drift in Influenza virus

- Slow and gradual change in proteins leads to change in strain of type A and B influenza viruses

Characteristics of flu

- Worst in elderly, best in children
- Abrupt onset of fever
- Headache but NO RUNNY NOSE
- NO VIREMIA and symptoms are confined to respiratory tract
- Makes more susceptible to bacterial infections - Staph. Aureus and Strep. Pneumonia in elderly after having flu